High-voltage power supply structure and image forming apparatus

Abstract

The present invention provides a high-voltage power supply structure and an image forming apparatus that can supply high voltage power using an output terminal and a power supply spring, and can prevent contact failures. [Solution] The high-voltage power supply structure comprises a high-voltage substrate 30, an imaging unit 20 supplied with high-voltage power, and a power supply spring 40 positioned between the high-voltage substrate 30 and the imaging unit 20. The high-voltage substrate 30 has a printed circuit board 31, a jumper wire 32 that contacts the power supply spring 40 and outputs high-voltage power, and a through hole 33 formed in the printed circuit board 31 so that the jumper wire 32 is exposed on the solder side of the printed circuit board 31. The imaging unit 20 has a guide rib 21 that positions the power supply spring 40 that contacts the jumper wire 32. The power supply spring 40 contacts the jumper wire 32 from the solder side of the printed circuit board 31 through the through hole 33. The guide rib 21 is inserted into the through hole 33 and positions the power supply spring 40 with the guide rib 21 protruding on the component side of the printed circuit board 31.

Description

Technical Field

[0001] The present disclosure relates to a high-voltage power supply structure and an image forming apparatus.

Background Art

[0002] In an electrophotographic image forming apparatus, it is necessary to supply high voltage in the image forming system. Patent Document 1 discloses a technique for supplying high voltage from a high-voltage substrate to an image forming system unit using a jumper wire and a coil spring (power supply spring). In this technique, a jumper wire is arranged as an output terminal for high-voltage output on the component surface of the high-voltage substrate, and a through hole is formed at a position corresponding to the jumper wire of the high-voltage substrate. The coil spring is arranged so as to contact the jumper wire through the through hole from the back side of the high-voltage substrate, and this coil spring serves as a power supply path to supply high voltage from the high-voltage substrate to the image forming system unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the technique of Patent Document 1 is used in an image forming apparatus, usually, high-voltage power supply is required at a plurality of locations, and in the high-voltage substrate, jumper wires are also arranged scattered at a plurality of locations. Therefore, it is necessary to align the coil springs with these plurality of jumper wires. In this case, when assembling the high-voltage substrate, it is difficult to assemble the high-voltage substrate in the vertical direction after aligning all the coil springs. For this reason, the high-voltage substrate is slid with the end portion of the coil spring in contact with the back surface of the high-voltage substrate to align the through hole exposing the jumper wire with the coil spring.

[0005] However, in Patent Document 1, since the jumper wire is soldered to the high-voltage substrate, the leads of the jumper wire are present on the back side (solder side) of the high-voltage substrate. Therefore, when the high-voltage substrate is slid to align the coil spring, the ends of the coil spring may catch on the leads of the jumper wire, potentially causing buckling of the coil spring and resulting in poor contact.

[0006] This disclosure has been made in view of the above-mentioned problems, and aims to provide a high-voltage power supply structure and an image forming apparatus that can supply high voltage power using an output terminal and a power supply spring and prevent contact failure. [Means for solving the problem]

[0007] To solve the above problems, the high-voltage power supply structure of the present disclosure comprises a high-voltage substrate that supplies high-voltage power, a supplied unit that receives high-voltage power from the high-voltage substrate, and a power supply spring provided on the supplied unit that serves as a high-voltage power supply path between the high-voltage substrate and the supplied unit. The high-voltage substrate is a printed circuit board with the surface facing the supplied unit being the solder surface, an output terminal disposed on the component surface on the back of the solder surface of the printed circuit board and in contact with the power supply spring to output high-voltage power, and a through hole formed in the printed circuit board so that the output terminal is exposed on the solder surface side of the printed circuit board. The supplied unit has a guide rib that positions the power supply spring that contacts the output terminal. The power supply spring contacts the output terminal from the solder surface side of the printed circuit board through the through hole, and the guide rib is inserted into the through hole and positions the power supply spring while protruding on the component surface side of the printed circuit board.

[0008] Furthermore, the above-mentioned high-voltage power supply structure can be configured such that the output terminal is a jumper wire located on the component side of the printed circuit board, the legs of the jumper wire are fixed by soldering on the solder side, and the length of the guide rib protruding from the component side of the printed circuit board is greater than or equal to the length of the jumper wire legs from the solder side of the printed circuit board.

[0009] Furthermore, the high-voltage power supply structure described above can be configured to include two guide ribs that face each other and sandwich the power supply spring in a plan view.

[0010] Furthermore, the high-voltage power supply structure described above can be configured such that the output terminals are two jumper wires arranged parallel to each other, and the two guide ribs are positioned opposite each other, with the jumper wires in between.

[0011] Furthermore, the high-voltage power supply structure described above may include a single guide rib positioned inside the power supply spring in a plan view.

[0012] Furthermore, the high-voltage power supply structure described above can be configured such that the output terminals are two jumper wires arranged parallel to each other, and one of the guide ribs is positioned between the jumper wires.

[0013] Furthermore, the image forming apparatus disclosed herein is an image forming apparatus having an image forming unit that performs image forming using electrophotographic technology and a high-voltage substrate that supplies high-voltage power to the image forming unit, characterized in that the high-voltage power supply structure described above is used to supply high-voltage power from the high-voltage substrate to the image forming unit. [Effects of the Invention]

[0014] The high-voltage power supply structure and image forming apparatus of this disclosure have the effect of preventing poor contact between the output terminal and the power supply spring by using guide ribs that position the power supply spring. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram showing the basic configuration of the image forming apparatus disclosed herein. [Figure 2] This is a perspective view showing the imaging unit and high-voltage substrate in an image forming apparatus. [Figure 3] This is an exploded perspective view showing the high-voltage substrate separated from the imaging unit. [Figure 4]It is a cross-sectional view schematically showing a power supply structure at one high-voltage power supply location. [Figure 5] It is a plan view and a cross-sectional view showing a state before the power supply spring is aligned at one high-voltage power supply location. [Figure 6] It is a plan view and a cross-sectional view showing a state where the power supply spring is aligned at one high-voltage power supply location. [Figure 7] In the second embodiment, it is a plan view and a cross-sectional view showing a state where the power supply spring is aligned at one high-voltage power supply location. [Figure 8] In the second embodiment, it is a plan view and a cross-sectional view showing a state where the power supply spring is aligned at one high-voltage power supply location. [Figure 9] In the third embodiment, it is a plan view and a cross-sectional view showing a state where the power supply spring is aligned at one high-voltage power supply location. [Figure 10] In the fourth embodiment, it is a plan view and a cross-sectional view showing a state where the power supply spring is aligned at one high-voltage power supply location.

Mode for Carrying Out the Invention

[0016] 〔First Embodiment〕 Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing the basic configuration of an image forming apparatus 10 of the present disclosure. Note that the image forming apparatus 10 in FIG. 1 is a color image forming apparatus capable of forming a color image, but the present invention is also applicable to a monochrome image forming apparatus that only forms a monochrome image.

[0017] As shown in FIG. 1, the image forming apparatus 10 includes a main body unit 11, an original reading unit 12, an original conveying device 13, and a paper feeding device 14.

[0018] The main body unit 11 has an image forming unit (printing unit) inside for forming (printing) an image on a recording sheet. The original document reading unit 12 is disposed above the main body unit 11 and reads the original document when making a copy of the original document. The original document conveying device 13 sequentially conveys the original documents placed on the original document set tray toward the original document placing table of the original document reading unit 12 in the automatic reading mode. The paper feeding device 14 includes at least one paper feeding cassette for stocking the recording sheets, separates the recording sheets one by one from the selected paper feeding cassette, and conveys them toward the main body unit 11. In the main body unit 11, an image is formed on the recording sheet sent from the paper feeding device 14.

[0019] The image data processed in the image forming apparatus 10 corresponds to a color image using each of the colors black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (for example, black). Therefore, the image forming apparatus 10 has four process units Pa to Pd associated with black, cyan, magenta, and yellow as the image forming unit. Each of the process units Pa to Pd forms a toner image corresponding to the image data using a known electrophotographic technique. The toner images formed by the process units Pa to Pd are primarily transferred to the intermediate transfer belt 111, and further secondarily transferred to the recording sheet by the secondary transfer device 112.

[0020] FIG. 2 is a perspective view showing the image forming system unit (the supplied unit) 20 and the high-voltage substrate 30 in the image forming apparatus 10 extracted. The image forming system unit 20 is a unit including the above-described process units Pa to Pd, the intermediate transfer belt 111, and the secondary transfer device 112. The image forming system unit 20 of the present embodiment includes an image forming unit 201 including the process units Pa to Pd and a secondary transfer unit 202 including the intermediate transfer belt 111 and the secondary transfer device 112, and is configured such that the secondary transfer unit 202 is disposed on top of the image forming unit 201 in an overlapping manner.

[0021] The high-voltage substrate 30 is positioned to face the power supply surface (the surface having the high-voltage input terminals) of the imaging unit 20. In this embodiment, the upper surface of the secondary transfer unit 202 is the power supply surface, and the high-voltage substrate 30 is positioned further above the secondary transfer unit 202. High-voltage power is supplied (high-voltage power supply) between the lower surface of the high-voltage substrate 30 and the upper surface of the secondary transfer unit 202. The high-voltage substrate 30 is equipped with various devices necessary for the printed circuit board 31, with its upper surface being the component surface for arranging the various devices, and its lower surface (i.e., the surface facing the imaging unit 20) being the solder surface. In this embodiment, high-voltage power can also be supplied to the image forming unit 201 from the high-voltage substrate 30 via the secondary transfer unit 202.

[0022] Next, the connection structure between the image-forming unit 20 and the high-voltage substrate 30 in this embodiment, that is, the high-voltage power supply structure from the high-voltage substrate 30 to the image-forming unit 20 (hereinafter simply referred to as the power supply structure), will be described. Figure 3 is an exploded perspective view showing the state in which the high-voltage substrate 30 has been separated from the image-forming unit 20.

[0023] As shown in Figure 3, the upper surface (power supply surface) of the image-making unit 20 is provided with a power supply spring 40 and a guide rib 21 at the high-voltage power supply points. The power supply spring 40 is a compression coil spring that serves as a power supply path for high-voltage electricity between the high-voltage substrate 30 and the image-making unit 20. The power supply spring 40 is positioned so as to be almost vertical to the upper surface of the image-making unit 20 (so that the direction of the natural length of the spring is almost parallel to the direction of the normal to the upper surface of the image-making unit 20). The lower end of the power supply spring 40 is directly or indirectly connected to a high-voltage input terminal (not shown) in the image-making unit 20. The guide rib 21 is for positioning the power supply spring 40 and is positioned close to the power supply spring 40 and is formed to be erected from the upper surface of the image-making unit 20. Details of the guide rib 21 will be described later. In this embodiment, high-voltage power is supplied to the image-making unit 20 at four locations, and a power supply spring 40 is provided at each of these four high-voltage power supply points. However, the number of high-voltage power supply locations is not particularly limited.

[0024] The high-voltage circuit board 30 is provided with jumper wires 32 and through holes 33 at the high-voltage power supply points. The jumper wires 32 are positioned on the component side of the high-voltage circuit board 30 and are fixed by soldering the leads of the jumper wires 32 on the solder side. In this embodiment, two jumper wires 32 are arranged in parallel at each high-voltage power supply point, and the distance between the two jumper wires 32 is narrower than the diameter of the power supply spring 40. The jumper wires 32 serve as output terminals on the high-voltage circuit board 30 and are bare wires not covered with an insulator. The through holes 33 are formed below the jumper wires 32 on the printed circuit board 31 so that the jumper wires 32 are exposed on the solder side of the high-voltage circuit board 30.

[0025] Figure 4 is a schematic cross-sectional view (a vertical cross-section passing between two jumper wires 32) showing the power supply structure at one high-voltage power supply point.

[0026] As shown in Figure 4, in the power supply structure of this embodiment, high-voltage power is supplied from the high-voltage substrate 30 to the image-making unit 20 by the jumper wire 32 and the power supply spring 40. That is, the upper end of the power supply spring 40 contacts the jumper wire 32 from the lower side of the high-voltage substrate 30 through the through hole 33. Since two jumper wires 32 are arranged in parallel at each high-voltage power supply point, the upper end surface of the power supply spring 40 can stably contact the jumper wire 32 while being parallel to the main surface of the high-voltage substrate 30. When a high voltage is applied to the jumper wire 32 in this state, high-voltage power can be supplied from the jumper wire 32 to the image-making unit 20 via the power supply spring 40.

[0027] When assembling the high-voltage substrate 30 to the image-forming unit 20, it is difficult to align all the power supply springs 40 at the high-voltage power supply points and then move the high-voltage substrate 30 perpendicular to the power supply surface of the image-forming unit 20 to assemble it. Therefore, the assembly procedure for the high-voltage substrate 30 involves sliding the high-voltage substrate 30 parallel to the power supply surface of the image-forming unit 20 with the ends (upper ends) of the power supply springs 40 in contact with the solder surface of the high-voltage substrate 30, thereby aligning the power supply springs 40 with the through-holes 33.

[0028] However, since the jumper wire 32 is soldered to the solder side of the high-voltage substrate 30, the soldered leads of the jumper wire 32 are present on the solder side. Furthermore, if the power supply structure of this disclosure is not adopted, specifically if the guide rib 21 is not provided at the high-voltage power supply point, the upper end of the power supply spring 40 may catch on the leads of the jumper wire 32 during the sliding process of the high-voltage substrate 30, causing the power supply spring 40 to buckle and resulting in poor contact (poor contact) with the jumper wire 32.

[0029] In the image forming apparatus 10, buckling of the power supply spring 40 can be prevented by providing guide ribs 21 at the high-voltage power supply points, thereby preventing contact failure of the power supply spring 40. The procedure for assembling the high-voltage substrate 30 to the image forming unit 20 will be described below with reference to Figures 5 and 6.

[0030] Figure 5 is a plan view and a cross-sectional view showing the state before the power supply spring 40 is aligned at one high-voltage power supply point. In the example of Figure 5, two guide ribs 21 are provided at one high-voltage power supply point (i.e., for one power supply spring 40). The two guide ribs 21 are positioned opposite each other in a plan view (viewed from the direction normal to the high-voltage substrate 30), with the power supply spring 40 sandwiched between them. The plan view shape of the guide ribs 21 is not particularly limited, but it is preferable that the inner surface of the guide rib 21 (the surface facing the power supply spring 40) is a concave surface that matches the outer circumference arc of the power supply spring 40, so that the power supply spring 40 can be stably held upright by the two guide ribs 21.

[0031] Furthermore, the length of the guide rib 21 (the height of the image-forming unit 20 from the power supply surface) is longer than the natural length of the power supply spring 40. As a result, the tip (upper end) of the guide rib 21 protrudes even further upward than the upper end of the power supply spring 40. Here, the amount of protrusion of the tip of the guide rib 21 from the upper end of the power supply spring 40 is denoted as L1. This protrusion amount L1 is set to be greater than the height L2 of the jumper wire 32's legs from the solder side of the high-voltage substrate 30.

[0032] As shown in Figure 5, before the power supply spring 40 is aligned, the tip of the guide rib 21 is in contact with the solder surface of the high-voltage substrate 30. Therefore, when aligning the power supply spring 40, the high-voltage substrate 30 is slid while the guide rib 21 and the high-voltage substrate 30 are in contact. At this time, the contact between the guide rib 21 and the high-voltage substrate 30 ensures a distance between the upper end of the power supply spring 40 and the solder surface of the high-voltage substrate 30. This distance is equal to the protrusion amount L1 of the guide rib 21. Also, since the protrusion amount L1 of the guide rib 21 is greater than the height L2 of the jumper wire 32's leg (L1 > L2), it is possible to prevent the upper end of the power supply spring 40 from getting caught on the leg of the jumper wire 32.

[0033] Figure 6 is a plan view and a cross-sectional view showing the state in which the power supply spring 40 is aligned at one high-voltage power supply point. As shown in Figure 6, when the power supply spring 40 is aligned with the through hole 33, the guide rib 21 can also be inserted into the through hole 33. In other words, the shape and dimensions of the through hole 33 in the high-voltage substrate 30 are designed so that the guide rib 21 can be inserted. In addition, the jumper wire 32 is also designed so as not to obstruct the insertion of the guide rib 21 into the through hole 33. In this embodiment, the two guide ribs 21 can be inserted into the through hole 33 when they are positioned opposite each other with the jumper wire 32 in between. In this case, the dimension of the through hole 33 in the direction parallel to the wiring direction of the jumper wire 32 is shorter than the dimension in the direction perpendicular to the wiring direction.

[0034] After the power supply spring 40 is aligned, the high-voltage substrate 30 can be assembled by moving it perpendicularly to the power supply surface of the image-making unit 20 while inserting the guide rib 21 into the through hole 33. As a result, the guide rib 21 is inserted into the through hole 33 and positions the power supply spring 40 with the guide rib 21 protruding from the opposite side (component side) of the jumper wire 32. At this time, the length of the guide rib 21 protruding from the component side of the printed circuit board 31 is greater than or equal to the length of the legs of the jumper wire 32 from the solder side of the printed circuit board 31, so that the power supply spring 40 can be assembled to make contact with the jumper wire 32.

[0035] This assembly allows the upper end of the power supply spring 40 to contact the jumper wire 32, and also allows for appropriate compression of the power supply spring 40. In this embodiment, the alignment stage of the power supply spring 40 prevents the power supply spring 40 from catching on the legs of the jumper wire 32 and causing buckling, thus ensuring good contact between the power supply spring 40 and the jumper wire 32. In other words, it prevents poor contact at high-voltage power supply points.

[0036] In this embodiment, it is preferable that the sliding direction when sliding the high-voltage substrate 30 for alignment is parallel to the wiring direction of the jumper wire 32 (arrow X direction in Figure 5). By sliding the high-voltage substrate 30 parallel to the wiring direction of the jumper wire 32, the tip of the guide rib 21 is less likely to get caught on the legs of the jumper wire 32, making it easier to perform the sliding operation for alignment.

[0037] Therefore, when there are multiple high-voltage power supply points on the high-voltage substrate 30, it is preferable to make the wiring direction of the jumper wires 32 the same at all high-voltage power supply points. However, due to space constraints on the high-voltage substrate 30, it may be difficult to make the wiring direction of the jumper wires 32 the same. However, even in such cases, the guide ribs 21 can prevent buckling of the power supply spring 40, and the effects of the present invention can be achieved.

[0038] [Second Embodiment] In the second embodiment, a modified example of the guide rib is shown. Figures 7 and 8 are a plan view and a cross-sectional view, respectively, showing the state in which the power supply spring 40 is aligned at one high-voltage power supply point in the second embodiment.

[0039] As shown in Figures 7 and 8, in this embodiment, a guide rib 22 is used instead of the guide rib 21 of the first embodiment. One guide rib 22 is positioned inside the power supply spring 40 in a plan view at one high-voltage power supply point. The guide rib 22 aligns the power supply spring 40 by being inserted between two jumper wires 32. In this way, even with only one guide rib 22, the high-voltage substrate 30 can be slid with the tip of the guide rib 22 in contact with the high-voltage substrate 30, preventing the power supply spring 40 from catching on the legs of the jumper wires 32 and buckling during the alignment stage of the power supply spring 40. Furthermore, by positioning one guide rib 22 inside the power supply spring 40, the power supply spring 40 can be stably held upright by the guide rib 22.

[0040] In the example shown in Figure 7, the tip of the guide rib 21 is a flat surface. In this case, it is possible to prevent the tip of the guide rib 22 from accidentally entering the outside of the jumper wire 32 during the sliding process of the high-voltage substrate 30.

[0041] On the other hand, in the example shown in Figure 8, the tip of the guide rib 21 is tapered (for example, roughly conical). In this case, the contact area between the tip of the guide rib 22 and the high-voltage substrate 30 can be reduced during the sliding process of the high-voltage substrate 30, making it less likely for the tip of the guide rib 22 to get caught on the legs of the jumper wire 32.

[0042] [Third Embodiment] In the third embodiment, another modification of the guide rib is shown. Figure 9 is a plan view and a cross-sectional view showing the state in which the power supply spring 40 is aligned at one high-voltage power supply point in the third embodiment.

[0043] As shown in Figure 9, in this embodiment, a guide rib 23 is used instead of the guide rib 21 of the first embodiment. Similar to the guide rib 22 of the second embodiment, one guide rib 23 is positioned inside the power supply spring 40 in a plan view at one high-voltage power supply point. However, the guide rib 23 has an elongated shape (e.g., oval shape, roughly rectangular shape) with longitudinal and transverse directions that are mutually perpendicular in a plan view. In this case, the longitudinal direction of the guide rib 23 in a plan view is parallel to the wiring direction of the jumper wire 32.

[0044] In this embodiment, the guide rib 23 has an elongated shape in plan view, which allows the guide rib 21 inserted inside the power supply spring 40 to more stably hold the power supply spring 40 upright. In the example of Figure 9, the tip of the guide rib 23 is tapered, similar to the guide rib 22 in Figure 8, but it may also be flat, similar to the guide rib 22 in Figure 7.

[0045] [Fourth Embodiment] The fourth embodiment shows yet another variation of the guide rib. Figure 10 is a plan view and a cross-sectional view showing the power supply spring 40 aligned at one high-voltage power supply point in the fourth embodiment.

[0046] As shown in Figure 10, this embodiment uses both the guide rib 21 of the first embodiment and the guide rib 23 of the third embodiment. Thus, the guide rib 21, which is positioned on the outside of the power supply spring 40, and the guide rib 23, which is positioned on the inside of the power supply spring 40, may be used in combination. Of course, it is also possible to use the guide rib 22 of the second embodiment instead of the guide rib 23.

[0047] The embodiments disclosed herein are illustrative in all respects and are not intended to be restrictive. Therefore, the technical scope of this disclosure is not to be interpreted solely by the embodiments described above, but rather by the claims. [Explanation of Symbols]

[0048] 10 Image forming apparatus 20 Image-making units (supplied units) 21, 22, 23 Guide ribs 30 High-voltage substrate 31 Printed circuit boards 32 Jumper wires (output terminals) 33 Through holes 40 Power supply spring

Claims

1. A high-voltage circuit board that supplies high-voltage power, A powered unit that receives high-voltage power from the high-voltage substrate, The system comprises a power supply spring provided on the unit to be supplied, which serves as a power supply path between the high-voltage substrate and the unit to be supplied, The high-voltage substrate comprises a printed circuit board with the surface facing the power supply unit as the solder surface, an output terminal disposed on the component surface on the back of the solder surface of the printed circuit board and in contact with the power supply spring to output high-voltage power, and a through hole formed in the printed circuit board so as to expose the output terminal to the solder surface side of the printed circuit board. The supplied unit has guide ribs for positioning the power supply spring that contacts the output terminal, The power supply spring contacts the output terminal by passing through the through hole from the solder side of the printed circuit board. The high-voltage power supply structure is characterized in that the guide rib is inserted into the through hole and positions the power supply spring while protruding towards the component side of the printed circuit board.

2. A high-voltage power supply structure according to claim 1, The output terminal is a jumper wire located on the component side of the printed circuit board, and the legs of the jumper wire are fixed by soldering on the solder side. A high-voltage power supply structure characterized in that the length of the guide rib protruding from the component side of the printed circuit board is greater than or equal to the length of the jumper wire leg from the solder side of the printed circuit board.

3. A high-voltage power supply structure according to claim 1, A high-voltage power supply structure characterized by including two guide ribs that are opposite each other with the power supply spring sandwiched between them in a plan view.

4. A high-voltage power supply structure according to claim 3, The output terminals consist of two jumper wires arranged parallel to each other. A high-voltage power supply structure characterized in that the two guide ribs are positioned opposite each other, with the jumper wire in between.

5. A high-voltage power supply structure according to claim 1, A high-voltage power supply structure characterized by including one of the guide ribs positioned inside the power supply spring in a plan view.

6. A high-voltage power supply structure according to claim 5, The output terminals consist of two jumper wires arranged parallel to each other. A high-voltage power supply structure characterized in that one of the guide ribs is positioned between the jumper wires.

7. An image forming apparatus comprising an image forming unit that performs image formation using electrophotographic technology, and a high-voltage substrate that supplies high-voltage power to the image forming unit, An image forming apparatus characterized in that a high-voltage power supply structure according to any one of claims 1 to 6 is used to supply high-voltage power from the high-voltage substrate to the image forming unit.

Images